PCIe tegra194 endpoint mode regulator question

[Niklas Cassel <cassel@kernel.org>]

Hello Tegra PCIe maintainers,

Looking at the device tree binding for Tegra PCIe endpoint mode:
Documentation/devicetree/bindings/pci/nvidia,tegra194-pcie-ep.yaml

We can see that 'vddio-pex-ctl-supply' is marked as required.

However, when inspecting the driver itself:
drivers/pci/controller/dwc/pcie-tegra194.c

regulator_enable(pcie->pex_ctl_supply);
is only called in tegra_pcie_config_controller().
tegra_pcie_init_controller() is called by tegra_pcie_config_rp()
(Root Complex mode), however regulator_enable(pcie->pex_ctl_supply);
is never called by tegra_pcie_config_ep() or pex_ep_event_pex_rst_deassert(),
or any other function called when the driver is using any of the
PCIe endpoint mode compatible strings.

So, I think there is something wrong here.

Either:
1) 'vddio-pex-ctl-supply' shouldn't be marked as required in the
   PCIe endpoint mode device tree binding (or perhaps not be there
   at all, since regulator_enable(pcie->pex_ctl_supply) is never called.)

2) drivers/pci/controller/dwc/pcie-tegra194.c should call
   regulator_enable(pcie->pex_ctl_supply) even in the endpoint mode case.


Looking forward to your feedback.


Kind regards,
Niklas